CVE-2026-55581

HighCVSS 8.4/10Last modified Sep 9, 2026

Description

mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, the default Docker security.yaml includes /bin/bash in allowed_executables, while security.go validates only the first token and checkBlockedPatternsAndCommands does not reject the shell command-mode flag -c. A caller of the shell_exec MCP tool can provide the command argument `/bin/bash -c <arbitrary-command>`, which passes validation and reaches executor.go, where parseCommand and exec.CommandContext execute the arbitrary command as mcpuser outside the intended allowlist. This issue is fixed in version 0.6.0.

Metrics

CVSS 3.1 8.4/10CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-78 CWE-183 CWE-1188

Affected software

No affected versions have been published.

Timeline

Published: Aug 25, 2026
Last modified: Sep 9, 2026
NVD status: Deferred

Related CVEs from 2026

CVE-2026-555828.4mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, the default security.yaml allows /CVE-2026-555837.6Twenty is an open-source CRM (customer relationship management) platform. Prior to 2.9.0, Twenty was vulnerable to a cross-workspace insecur CVE-2026-555847.5phpSysInfo is a customizable PHP script that displays system information. Prior to 3.4.6, the PSI_ALLOWED access-control check in read_confi CVE-2026-555858.8QWED is open-source AI verification infrastructure for deterministic verification of LLM outputs, tool calls, code, schemas, and agent state CVE-2026-555866.6SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, a crafted CHM file can supply malformed LZX Huffman code lengths to m CVE-2026-555878.1AliasVault is a privacy-first password manager with built-in email aliasing. Prior to 0.29.4, the AliasVault browser extension passkey provi CVE-2026-555886.5ORAS (OCI Registry As Storage) is a CLI and library for managing artifacts in OCI registries. In ORAS CLI versions up to and including 1.3.2 CVE-2026-55596.3A vulnerability has been found in AntaresMugisho PyBlade 0.1.8-alpha/0.1.9-alpha. The affected element is the function _is_safe_ast of the f CVE-2026-555906.1CakePHP Authentication is an authentication plugin for CakePHP that can also be used in PSR-7 based applications. Prior to 2.11.1, 3.3.6, an CVE-2026-555915.8Signal K Server is a server application that runs on a central hub in a boat. Prior to 2.28.0, makeRemoteRequest() in src/serverroutes.ts ac CVE-2026-555923.9Dashy is a self-hostable personal dashboard. Prior to 4.3.7, Dashy's workspace view trusts the url query parameter and assigns it directly t CVE-2026-555936.5Froxlor is open source server administration software. Prior to 2.3.8, the standalone lib/ajax.php entry point bypasses the centralized requ